Technical Abstract:
Both environmental and economic concerns have led to the development of fish-meal free diets for salmonids. The ability of rainbow trout to efficiently utilize plant-based diets for growth and reproduction, and the genetic variation within populations for these traits, has not been thoroughly examined. In a previous study we used microsatellites to determine the pedigree of the top 1% and bottom 1% of progeny in a commercial growth trial of 20 full-sib families reared in a common environment. Half of the fish from each family were fed a standard fish-meal based diet and the other half was fed a plant-protein (gluten) based diet. The family rankings were similar when either diet was fed, indicating no genotype X diet interaction is present in that commercial trout strain. In the present study, growth and reproductive performance of a pedigreed population from another commercial strain were assessed feeding both plant-based and traditional fish-meal diets. Families (95 full-sib and 47 half-sib) were reared in a common environment and parentage assignment performed on 1000 fish fed each diet. Growth and reproductive performance of families fed the plant-based diet were compared to identical families fed the control (fish-meal/oil) diet. Statistical analysis of mean family performance was used to assess genotype x diet interactions.